A number of systems are available for utility companies to obtain data from utility meters at subscriber locations without having to send service personnel to the subscriber location to read and record meter information. For example, U.S. Pat. No. 5,359,641, to Schull et al, discloses a telemetry system for accessing equipment at subscriber locations through a switching network. Control equipment in the telemetry system is configured to identify the signaling modes for loop networks connected to the subscriber locations. The signaling mode (e.g., a no signaling mode or an identified signaling mode of specified duration) for each subscriber location is stored with other customer information, as well as a reference identification number associated with equipment at the subscriber location. The control system comprises trunks which indicate to the central office switch that connections being requested by the control system are to be made with ringing suppression. The system disclosed in the Schull et al patent is therefore disadvantageous because it requires modification of the central office switch in order to communicate with the control system, among other reasons. Most telephone companies are not willing to modify a digital switch in order to provide only one new service such as telemetry.
A number of systems have been developed to report conditions such as power usage meter levels by initiating a telephone call to a utility company from a subscriber location. See, for example, U.S. Pat. No. 4,086,434, to Bocchi, U.S. Pat. No. 4,487,892, to Shelley, U.S. Pat. No. 5,239,575, to White et al, and U.S. Pat. No. 4,394,540, to Willis et al. These systems are programmed to initiate a telephone call to a host computer of a utility company, for example. The telemetry reporting is typically conducted by initiating telephone calls to the host computer at predetermined intervals, such as once a month. Alternatively, equipment at a subscriber location can monitor a telephone line for a polling signal from a host computer. Following detection of the polling signal, the equipment calls the host computer to transfer utility meter readings. These systems are disadvantageous for a number of reasons. For example, they can interfere with the establishment of voice calls to a telephone connected to the telephone line at the subscriber location. Further, they do not guarantee that a utility company or other service provider will be called by the subscriber, that is, the subscriber's telephone line may be out of order or disconnected or the subscriber device for connecting to a remote system may have failed. It is disadvantageous to require utility companies to passively monitor whether or not a subscriber has called and to ascertain reasons (e.g., system failure) for his or her failure to do so. It is more advantageous to centralize the functions of utility and other service providers to actively monitor a subscriber's usage of a utility or other service such as an on-line information service by initiating the telephone connection to the subscriber.
Other systems have been provided which allow equipment at the subscriber location to interrogate incoming calls using data identifing a calling party in order to determine whether or not to answer the incoming telephone call. For example, U.S. Pat. No. 5,351,289, to Logsdon et al, discloses apparatus for receiving and demodulating caller identification signals, which are provided by a telephone company during the silent interval between the first and second power ring signals of an incoming call, to control an electronic switching device. The apparatus is configured to maintain the switching device in a non-conductive state while caller identification data (i.e., CallerID) is received and analyzed to determine whether or not to suppress subsequent power ring signals. If the telephone call is being initiated by a selected calling party, the apparatus is programmed to operate the switching device in a conductive state and allow the incoming telephone call to pass to a telecommunications device connected to the apparatus. The apparatus is connected between a central office and a telecommunications device and comprises a single terminal adapter for connection to the telecommunications device (e.g., a facsimile machine, a modem, an answering machine or a standard telephone set). The apparatus is disadvantageous because it interferes with establishing voice calls. The apparatus only monitors the connection of the telecommunications device to the apparatus, and not to the telephone line itself to determine whether a handset has gone off-hook. Further, once CallerID is used to determine whether or not to close the switching device and connect an incoming call to the telecommunications device, the CallerID is no longer available for the telecommunications device to identify the calling party. In addition, the apparatus cannot be used with more than one telecommunications device without providing another telephone line.
U.S. Pat. No. 5,206,900, to Callele, discloses an apparatus for interfacing a telephone to a telephone network and for receiving caller identification information from incoming telephone calls. The apparatus can acknowledge receipt of the caller identification information to the incoming calling party, can cause the incoming call to be answered or not answered, and can forward the caller identification information to a subscriber at a predetermined location. However, the apparatus disclosed in then Callele patent does not provide for the connection of the calling party to the called party. Instead, the apparatus operates as an automated attendant for forwarding information to the called party so that he or she can return the call at a later time if desired.
U.S. Pat. No. 5,267,307, to Izumi et al, and U.S. Pat. No. 5,396,548, to Bayerl et al, also disclose systems which receive and analyze information identifying a calling party. These systems, however, do not operate to provide a subscriber, who has a single non-dedicated telephone line, with information regarding the identification of the calling party following ring suppression. In contrast, the Izumi et al patent uses the information regarding the calling party to determine how to ring extension terminal equipment in a private branch exchange or a key telephone system. The Bayerl et al patent uses calling party identification during a silent interval between ring signals on an incoming call to determine which of a number of stations connected to a central office or PBX the incoming call should be directed to. The system is programmed to transmit the caller identification information between successive ring signals for receipt by other stations.